Hey guys, I have never done this before and have purused Steve's examples in his books but I'm afraid I still don't get it, although I've probably read enough about it to give it a good try and be reasonably successful, I'd like to be more confident in what I'm doing before I cut into one. I've done lamb many times before, but not a leg. I don't need a recipe or cooking advice, I think Steve has that covered for me. I found a video on carving leg of lamb but nothing on butterflying. Any ideas?

Airfoil,
If you have a Costco or Sam’s club in your area, they both sell already butterflyed leg of lamb. It’s an Australian lamb (if you don’t mind that) and it comes wrapped in webbing. If you still want to do yourself, just go ahead and try. You really can’t mess it up. In worse case scenario, you can roll it backup (tucking in the odd shaped pieces) and tie it up with some butcher twin. This way it will be in a shape of every day roast and no one will know the difference.
Good luck and let us know how it turned out.

I don't eat much lamb so I've not even seen the leg up close therefore this may not be much help:

In "How to Grill" the recipe for Jamaican Jerk Pork shows how to butterfly a pork shoulder ham. All I had was a Boston Butt which has a shoulder blade instead of a leg bone. The slicing was a little different than in the illustration but the technique was still the same. I just had to figure out how to follow the bone.